Saturday, 26 December 2009

Joseph Rock Rocks

When I decided to plant a rowan in the front garden I chose the yellow berried variety Sorbus 'joseph rock' because the autumnal combination of yellow berries against alizarin foliage is just superb.  My ulteria motive of course was lots of berries to pull the birds.  When I got the tree home, I was puzzled to read on the label that birds wouldn't eat the yellow berries.  Complete rubbish! They love them.

The car park at work has a couple of these rowans in one corner and at lunchtime on the last day before the christmas holiday break they were absolutely covered in berries and absolutely heaving with 4 of the 5 winter thrushes - redwing (the most numerous), fieldfare, blackbird and mistle thrush (but no song thrush to complete the set).  By hometime at 5pm they were stripped bare and the birds were long gone.

For me, the arrival of the winter thrushes from the far north is another one of our great annual events. The BTO has tracked the arrival of fieldfares through its birdtrack scheme and published a graph for the last three years on it web site (click here).  This shows a remarkable consistency in arrival dates and numbers.  The recent peak in records seems to coincide with my sightings in Durham.

A propos of nothing of the enjoyable spin-offs of natural history blogging is wandering off down the side alleys that present themselves at random.   So, who was Joseph Rock anyway and why the tree named after him?  Turns out he was an interesting character who travelled a lot in China collecting plants and taking photos in the early 20th century.  The report I found here, says of the Joseph Rock rowan:-

'One of his best-known yet least-documented finds cannot be unequivocally attributed to Rock. It appeared as a chance seedling among Rock’s collections at the Royal Botanic Garden in Edinburgh. No record could be found of an herbarium specimen or field note, and some even believe it to be a hybrid.'

So there you have it.


  1. Interesting - the dogma is that bird vision is most sensitive at the red end of the spectrum, so they are drawn to red berries... but I used to have a white berried Sorbus cashmeriana in my garden and the berries barely had time to ripen before the birds ate them....

  2. Hi Phil. I recall reading that diurnal birds see well in ultra violet part of the spectrum - I think it was in an article about hovering kestrels tracking voles through their urine trails that fluoresce in ultra violet light, rather than by sight of the beast itself. So it could be that yellow and white berries zing out like beacons - especially on a bright ultraviolety day like this one was.